Conditional Insert

I need to do a conditional insert. This is what I have tried, it does not work.
What am I doing incorrectly?

IF (SELECT COUNT(*) FROM TBL1 INNER JOIN
TBL2 ON TBL1.MODEL_ID = TBL2.MODEL_ID INNER JOIN
TBL3 ON TBL1.PRO_TYPE = TBL3.TYPE INNER JOIN
TBL4 ON TBL1.PRO_SITE = TBL4.WHDESC) > 0

INSERT INTO TBL5
SELECT TBL1.PRO_SITE, TBL1.MODEL_ID,
TBL1.NUM_SLOTS, TBL1.TARGET_DAYS, GETDATE() AS Expr1,
TBL3.TYPE_ID, NULL AS Expr2, TBL1.NUM_SLOTS AS Expr3, NULL AS Expr4, NULL
AS Expr5, 0 AS RAMP
FROM TBL1 INNER JOIN
TBL2 ON TBL1.MODEL_ID = TBL2.MODEL_ID INNER JOIN
TBL3 ON TBL1.PRO_TYPE = TBL3.TYPE INNER JOIN
TBL4 ON TBL1.PRO_SITE = TBL4.WHDESC

UPDATE TBL5
SET TEAMS=0
GO
UPDATE TBL5
SET TEAMS = (SELECT NUM_SLOTS
FROM TBL6 R1
WHERE (R1.TEAM_ID = TBL5.TEAM_ID)
)
WHERE (TEAM_ID =
(SELECT TEAM_ID
FROM TBL6 R3
WHERE (R3.TEAM_ID = TBL5.TEAM_ID)))
GO
UPDATE TBL5
SET TOTALTEAMS = TEAMS + RAMP
GO

I need to do a conditional because sometimes the select that returns data contains no records.

Thanks...Try this:

IF EXISTS
(SELECT 1
FROM TBL1
INNER JOIN TBL2 ON TBL1.MODEL_ID = TBL2.MODEL_ID
INNER JOIN TBL3 ON TBL1.PRO_TYPE = TBL3.TYPE
INNER JOIN TBL4 ON TBL1.PRO_SITE = TBL4.WHDESC)
BEGIN
UPDATE <stuff here>
END
ELSE
BEGIN
INSERT <stuff here>
END